Uyghur riders saved Tang capitals—then ruled the steppe
For about a century in the mid-eighth and ninth centuries the Uyghur Khaganate, the Toquz Oghuz “Nine Tribes,” dominated Inner Asia. After Tang’s 751 Talas defeat, Uyghurs filled the vacuum—and in 757 lent some 4,000 horsemen to retake Chang’an and Luoyang.
Once a Tiele tribe under Turkic overlords, the Uyghurs sided with the Tang against Tibetans and Turks by 627 and broke with the Turks entirely after 657. In 742 they joined Karluks and Basmyls against the Second Turkic Khaganate, then turned on the Basmyls. Kutlug I Bilge Khagan claimed supremacy, and in 745 the head of the last Göktürk khagan was sent to the Tang. His son Bayanchur, ruling from 747, spent profits from Tang trading posts on the capital Ordu-Baliq and a second city, Bai Baliq, up the Selenga.
When An Lushan rebelled in 755, Emperor Suzong sought Bayanchur’s help, and in 757 Uyghur horsemen helped retake both capitals. In 758 Bayanchur crushed the Yenisei Kyrgyz and executed their khan; that same year Uyghur and Abbasid envoys quarrelled at the Tang palace door over who should enter first. His son Bögü switched sides in 762 to help the Tang retake Luoyang, then looted it and burned temples where citizens sheltered, killing over 10,000.
In 779 Bögü planned to invade China on the advice of Sogdian courtiers, but his uncle Tun Baga Tarkhan killed him along with nearly 2,000 relatives, supporters, and Sogdians. After Uyghur tribute-bearers were murdered leaving Chang’an in 780, Tun extracted 1,800,000 strings of cash, paid in gold and silk. The Uyghurs drove Tibetans from Lingzhou in 791, took Gaochang in 803, and seized Liang Province in 808.
Collapse came fast. In 839 a minister, Qasar, seized power with 20,000 Shatuo horsemen just as famine, disease, and a harsh winter killed much of the livestock. In 840 a rival invited the Yenisei Kyrgyz, whose roughly 80,000 riders razed Ordu-Baliq and beheaded Qasar. The Tang joined the war, ordered Manichaean priests killed in 843, and defeated the last claimants by 847.
Source: Uyghur Khaganate
